JP2015052439A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger which includes a flat tube and a header collection tube, and, when operating in a function as an evaporator, secures more circulation amount of liquid refrigerant into a plurality of flat tubes positioned in a lower part of a heat exchange region of a bottom stage of a main heat exchange part.SOLUTION: In a second header collection tube (70) of a heat exchanger (23) to which one end of a main heat exchange part (51) and one end of an auxiliary heat exchange part (52) are connected, a plurality of header spaces (71a-71c) of a main header part (71) corresponding to a plurality of main heat exchange regions (51a-51c) of the main heat exchange part (51) and a plurality of header spaces (72a-72c) of an auxiliary header part (72) corresponding to a plurality of auxiliary heat exchange regions (52a-52c) of the auxiliary heat exchange part (52) are connected to each other through connection tubes (76-78), respectively. The connection tubes (76-78) are horizontally opened in respective lower portions of the plurality of header spaces (71a-71c) of the main header part (71).

Description

  The present invention relates to a heat exchanger that includes a plurality of flat tubes and a pair of header collecting tubes and is connected to a refrigerant circuit that performs a refrigeration cycle to exchange heat between the refrigerant and air.

  Conventionally, a heat exchanger having a plurality of flat tubes and a pair of header collecting tubes is known. For example, Patent Document 1 and Patent Document 2 disclose this type of heat exchanger. In the heat exchangers of each of these patent documents, one header collecting pipe is erected on each of the left end and the right end of the heat exchanger, and a plurality of flat tubes extends from the first header collecting pipe to the second header collecting pipe. Has been placed. And the heat exchanger of each of these patent documents heat-exchanges the fluid which flows the inside of a flat tube with the air which flows the outside of a flat tube. In addition, this type of heat exchanger is connected to a refrigerant circuit that performs a refrigeration cycle, and functions as an evaporator or a condenser.

JP 2005-003223 A JP 2006-105545 A

  By the way, in the heat exchanger functioning as an evaporator, moisture in the air may adhere as frost. The frost adhering to the heat exchanger hinders heat exchange between the air and the refrigerant. Therefore, the heat exchanger performs a defrosting operation by functioning as a condenser so that the frost attached thereto is melted by the high-pressure gas refrigerant. At that time, depending on the structure of the heat exchanger, it may take a long time to melt all the frost adhered to the heat exchanger. Here, the problem will be described with reference to FIG.

  The heat exchanger (900) shown in FIG. 9 includes a large number of flat tubes, one header collecting tube (903, 906) connected to each flat tube, and fins. In addition, in FIG. 9, illustration of a flat tube and a fin is abbreviate | omitted.

  The heat exchanger (900) includes a main heat exchange section (901) having three main heat exchange areas (901a to 901c) and an auxiliary heat exchange section (902) having three auxiliary heat exchange areas (902a to 902c). It is divided into. The first header assembly portion (903) has a main header portion (904) to which one end of a flat tube of each main heat exchange region (901a to 901c) of the main heat exchange portion (901) is connected, and an auxiliary heat exchange portion An auxiliary header portion (905) to which one end of the flat tube of each auxiliary heat exchange region (902a to 902c) of (902) is connected is formed. Three main partial spaces (907a, 907b, 907c) to which the other ends of the flat tubes of the main heat exchange regions (901a to 901c) of the main heat exchange unit (901) are connected to the second header assembly (906). ) And three auxiliary partial spaces (908a, 908b, 908c) to which the other ends of the flat tubes of the auxiliary heat exchange regions (902a to 902c) of the auxiliary heat exchange unit (902) are connected. ) Having an auxiliary header portion (908). The first main partial space (907a) of the main header portion (907) communicates with the third auxiliary partial space (908c) below the second header assembly portion (906) and the second main portion. The space (907b) is connected to the first auxiliary partial space (908a) by a connecting pipe (910), and the third main partial space (907c) is connected to the second auxiliary partial space (908b) by a connecting pipe (911). Has been.

  Therefore, in this heat exchanger (900), the first main heat exchange area (901a) of the main heat exchange section (901) is connected in series with the third auxiliary heat exchange area (902c) of the auxiliary heat exchange section (902). The second main heat exchange area (901b) of the main heat exchange section (901) is connected in series with the first auxiliary heat exchange area (902a) of the auxiliary heat exchange section (902), and the main heat exchange section (901) The third main heat exchange area (901c) is connected in series with the second auxiliary heat exchange area (902b) of the auxiliary heat exchange section (902).

  When the heat exchanger (900) functions as an evaporator, the refrigerant that has flowed into the auxiliary header part (905) of the first header assembly part (903) passes through the auxiliary heat exchange region (902a to 902a) of the auxiliary heat exchange part (902). 902c) and then the main heat exchanging regions (901a to 901c) of the main heat exchanging portion (901) from the auxiliary header portion (908) of the second header collecting portion (906) through the main header portion (907). And then flows into the main header part (904) of the first header assembly part (903). Then, while passing through the auxiliary heat exchange region (902a to 902c) of the auxiliary heat exchange unit (902) and the main heat exchange region (901a to 901c) of the main heat exchange unit (901) in order, the heat is absorbed from the air and evaporated. . While the heat exchanger (900) functions as such an evaporator, frost may adhere to the surface of the heat exchanger (900).

  When the defrosting operation is started, the refrigerant flow is in the reverse direction, and the high-temperature and high-pressure gas refrigerant discharged from the compressor flows into the main header part (904) of the first header assembly part (903), Subsequently, it flows into the flat tube in the main heat exchange area (901a to 901c) of the main heat exchange section (901). The gas refrigerant flowing into the flat tube dissipates heat and condenses with respect to the frost, and the frost attached to the heat exchanger (900) is heated and melted by the heat release of the gas refrigerant.

  However, in a refrigeration apparatus having a heat exchanger, refrigeration oil that lubricates the compressor is included in the refrigerant and circulates in the refrigerant circuit. From this configuration, the inventors of the present application have found the following problems.

  That is, the refrigerating machine oil contained in the refrigerant is easy to dissolve in the liquid refrigerant, but difficult to dissolve in the gas refrigerant. Further, in the heat exchanger (900) shown in FIG. 9, when the heat exchanger (900) functions as an evaporator, each auxiliary heat exchange region (902a to 902a) of the auxiliary heat exchange unit (902) is used. The liquid refrigerant that has flowed into 902c) flows into the auxiliary partial spaces (908a to 908c) of the second header assembly portion (906). Here, the liquid refrigerant that has flowed into the uppermost third auxiliary partial space (908c) rises directly upward toward the first main partial space (907a) located above the third auxiliary partial space (908c). It flows into a plurality of flat tubes that open horizontally in the main partial space (907a). Due to the configuration, most of the liquid refrigerant flowing into the first main partial space (907a) flows into a plurality of flat tubes opened in the upper space in the first main partial space (907a). The liquid in the flat tube located below the first main heat exchange region (901a) of the main heat exchange section (901) is difficult to flow into the plurality of flat tubes that open to the lower space in the main partial space (907a). The circulation volume of the refrigerant is small. As a result, most of the liquid refrigerant in the flat tube located below the first main heat exchange region (901a) becomes a gas refrigerant and becomes overheated, and the refrigerating machine oil contained in the gas refrigerant becomes the first refrigerant heat. It accumulates in a plurality of flat tubes located below the main heat exchange region (901a).

  Thus, in the first main heat exchange region (901a), a large amount of refrigerating machine oil is accumulated in the lower part and the amount of accumulation is small in the middle and upper part. In this situation, the defrosting operation is started. Then, the refrigerant gas flowing into the main header portion (903) of the first header assembly portion (903) from the refrigerant pipe (909) has a large amount of refrigerating machine oil accumulated in the lower portion of the first main heat exchange region (901a). It becomes a resistance and hardly flows into the lower part of the first main heat exchange region (901a), but flows into the middle part and the upper part thereof. As a result, the progress of defrosting in the lower part of the first main heat exchange region (901a) is slow, and even if defrosting in the middle part and upper part is completed, the defrosting in the lower part of the first main heat exchange region (901a) There is a drawback that the defrosting operation cannot be completed until the defrosting is completed, and the defrosting operation time becomes long.

  The present invention has been made in view of such problems, and the object thereof is a lower part of the lowermost heat exchange region of the main heat exchange part in a heat exchanger having a flat tube and a header assembly part. The defrosting operation is completed early by limiting the amount of refrigerating machine oil that accumulates in the flat tube located at a small amount.

  In order to achieve the above object, in the present invention, when functioning as an evaporator, it flows from the header assembly portion to the plurality of flat tubes below the heat exchange region located at the bottom of the main heat exchange portion. A configuration that can secure a large amount of liquid refrigerant to be used is adopted.

  Specifically, the heat exchanger according to the first aspect of the present invention includes a main heat exchange section (51) and an auxiliary heat exchange section (52) in which a plurality of flat tubes (33) each having a refrigerant passage formed therein are vertically divided. And a header assembly part (70) having a main header part (71) and an auxiliary header part (72) to which ends of both the heat exchange parts (51), (52) are connected, and the main heat exchange Section (51) and auxiliary heat exchanging section (52) are each divided into a plurality of heat exchanging regions (51a to 51c) and (52a to 52c) in the upper and lower directions, and the refrigerant performs the auxiliary heat exchanging during operation as an evaporator. The main heat exchange from the main header part (71) of the header assembly part (70) through the auxiliary header part (72) of the header assembly part (70) from the plurality of heat exchange regions (52a to 52c) of the part (52) A heat exchanger having a refrigerant flow path that circulates in a plurality of heat exchange regions (51a to 51c) of the section (51), the auxiliary heat exchange section of the auxiliary header section (72) of the header assembly section (70) Header empty corresponding to multiple heat exchange areas (52a-52c) in (52) (72a to 72c) and a connecting pipe for connecting the header space (71a to 71c) corresponding to the plurality of heat exchange regions (51a to 51c) of the main heat exchange section (51) of the main header section (71) ( 76 to 78), and the plurality of connecting pipes (76 to 78) are respectively connected to the main heat in the header space (72a to 72c) corresponding to the main header portion (71) of the header assembly portion (70). The heat exchanger region (51a to 51c) corresponding to the exchanger (51) has a horizontal opening at the bottom.

  In the heat exchanger of the first invention, when the present heat exchanger functions as an evaporator, the liquid refrigerant is supplied from the plurality of heat exchange regions of the auxiliary heat exchanger to the plurality of auxiliary header portions of the header assembly portion. After flowing into the header space, each flows into the lower part of the plurality of header spaces of the main header part from the horizontal direction through the connecting pipes, so that the plurality of heat exchange regions of the main heat exchange part are respectively located at the lower part A sufficient amount of liquid refrigerant will also flow into the flat tube. Therefore, the overheating state of the refrigerant in these flat tubes is suppressed, the amount of refrigerating machine oil that accumulates in these flat tubes decreases, and the amount of refrigerating machine oil that accumulates in each heat exchange region of the main heat exchanger mutually Equalize. Therefore, during the subsequent defrosting operation, the gas refrigerant flowing into each heat exchange region of the main heat exchanger has the same flow resistance due to almost the same amount of refrigeration oil. The defrosting operation is completed at an early stage as the defrosting in each heat exchange region progresses to the same degree.

  According to a second aspect of the present invention, in the heat exchanger, the end surface openings of the plurality of connecting pipes (76 to 78) are respectively in the corresponding heat exchange regions (51a to 51c) of the main heat exchange unit (51). It is characterized by facing the end surface opening of the flat tube (33a) located in the lower part.

  In the heat exchanger according to the second aspect of the invention, at the lower part of each heat exchange region of the main heat exchange part, the end face opening of the connecting pipe faces the end face opening of the flat tube located below the heat exchange region. Therefore, during operation in which the present heat exchanger functions as an evaporator, the refrigerant that has flowed in from each communication pipe is likely to flow through the flat tube below the corresponding heat exchange region. Therefore, the overheating state of the refrigerant in these flat tubes is further suppressed, and the amount of refrigerating machine oil that accumulates in these flat tubes is further reduced, so that the defrosting operation is completed earlier.

  According to a third aspect of the present invention, in the heat exchanger, a header space corresponding to a lowermost heat exchange area (52a) of the auxiliary heat exchange section (52) of the auxiliary header section (72) of the header assembly section (70). (72a) and the header space (71a) corresponding to the lowermost heat exchange area (51a) of the main heat exchange part (51) of the main header part (71) are connected by a connection pipe (78). It is characterized by that.

  In the heat exchanger of the third invention, when the heat exchanger functions as an evaporator, when the liquid refrigerant flows into a plurality of heat exchange regions located above and below the auxiliary heat exchange section, it acts on the liquid refrigerant. Due to the gravity, a large amount of liquid refrigerant easily flows in the lowermost heat exchange area, and the lowermost heat exchange area becomes liquid-rich. Such a liquid-rich liquid refrigerant flows from the lowermost header space of the auxiliary header portion of the header assembly portion into the lower portion of the lowermost header space of the main header portion from the horizontal direction via the connecting pipe, and main heat exchange Since a sufficient amount of liquid-rich refrigerant flows into the flat tubes located in the lower part of the heat exchange area at the bottom of the section, the amount of refrigeration oil that accumulates in these flat tubes is further reduced, and the defrosting operation is further reduced. It will be completed early.

  According to a fourth aspect of the present invention, in the heat exchanger, a header space corresponding to the uppermost heat exchange area (52c) of the auxiliary heat exchange section (52) of the auxiliary header section (72) of the header assembly section (70). (72c) and the header space (71a) corresponding to the lowermost heat exchange area (51a) of the main heat exchange part (51) of the main header part (71) are connected by a connection pipe (78). It is characterized by that.

  In the heat exchanger according to the fourth aspect of the present invention, when the heat exchanger functions as an evaporator, the liquid refrigerant flows into the plurality of heat exchange regions located above and below the auxiliary heat exchange unit as described above. Since a large amount of liquid refrigerant tends to flow in the lowermost heat exchange region due to gravity acting on the uppermost heat exchange region, a gas-rich state occurs in the uppermost heat exchange region. However, the gas-rich refrigerant that has flowed into the uppermost heat exchange region flows into the uppermost header space of the auxiliary header portion of the header assembly portion, and then via the connecting pipe, the lowermost header space of the main header portion. 9 from the horizontal direction, the configuration of the conventional heat exchanger shown in FIG. 9 (that is, the uppermost header space of the lower header portion of the header assembly portion and the lowermost portion of the upper header portion above it) Compared to the configuration in which the header space is not connected to the header pipe and communicated inside the header assembly portion), a relatively large amount of liquid refrigerant is present in the lower portion of the lowermost heat exchange region of the main heat exchange portion. The amount of refrigerating machine oil that flows into the flat tubes and accumulates in these flat tubes decreases, and the defrosting operation is completed earlier.

  According to the heat exchanger of the first aspect of the invention, when functioning as an evaporator, the liquid refrigerant is sufficiently allowed to flow into the flat tubes located below the plurality of heat exchange regions of the main heat exchange section. Therefore, the amount of refrigerating machine oil that accumulates in each heat exchange area of the main heat exchanger can be equalized, and defrosting in each heat exchange area can proceed to the same extent during the defrosting operation. Operation can be completed early.

  According to the 2nd-4th invention, since the quantity of the refrigerating machine oil which accumulates in the flat tube of the lower part of each heat exchange area | region of the main heat exchange part at the time of the operation | movement which functions as an evaporator can be reduced more, defrosting Driving can be completed earlier.

FIG. 1 is a refrigerant circuit diagram illustrating a schematic configuration of an air conditioner including the outdoor heat exchanger according to the first embodiment. FIG. 2 is a front view showing a schematic configuration of the outdoor heat exchanger. FIG. 3 is a partial cross-sectional view showing the front of the outdoor heat exchanger. FIG. 4 is a cross-sectional view of the outdoor heat exchanger showing a part of the AA cross section of FIG. 3 in an enlarged manner. FIG. 5 is an enlarged cross-sectional view showing a part of the front surface of the outdoor heat exchanger. FIG. 6 is a partial cross-sectional view showing the front of the outdoor heat exchanger of the second embodiment. FIG. 7 is a front view showing a schematic configuration of the outdoor heat exchanger of the third embodiment. FIG. 8 is a partial cross-sectional view showing the front of the outdoor heat exchanger. FIG. 9 is a diagram showing a schematic configuration of a conventional heat exchanger.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

(First embodiment)
A first embodiment of the present invention will be described. The heat exchanger of the present embodiment is an outdoor heat exchanger (23) provided in the air conditioner (10). Hereinafter, the air conditioner (10) will be described first, and then the outdoor heat exchanger (23) will be described in detail.

-Air conditioner-
The air conditioner (10) will be described with reference to FIG.

<Configuration of air conditioner>
The air conditioner (10) includes an outdoor unit (11) and an indoor unit (12). The outdoor unit (11) and the indoor unit (12) are connected to each other via a liquid side connecting pipe (13) and a gas side connecting pipe (14). In the air conditioner (10), the refrigerant circuit (20) is formed by the outdoor unit (11), the indoor unit (12), the liquid side communication pipe (13), and the gas side communication pipe (14).

  The refrigerant circuit (20) is provided with a compressor (21), a four-way switching valve (22), an outdoor heat exchanger (23), an expansion valve (24), and an indoor heat exchanger (25). ing. The compressor (21), the four-way switching valve (22), the outdoor heat exchanger (23), and the expansion valve (24) are accommodated in the outdoor unit (11). The outdoor unit (11) is provided with an outdoor fan (15) for supplying outdoor air to the outdoor heat exchanger (23). On the other hand, the indoor heat exchanger (25) is accommodated in the indoor unit (12). The indoor unit (12) is provided with an indoor fan (16) for supplying room air to the indoor heat exchanger (25).

  The refrigerant circuit (20) is a closed circuit filled with a refrigerant. In the refrigerant circuit (20), the compressor (21) has its discharge pipe connected to the first port of the four-way switching valve (22) and its suction pipe connected to the second port of the four-way switching valve (22). Has been. In the refrigerant circuit (20), the outdoor heat exchanger (23), the expansion valve (24), and the indoor heat exchanger are sequentially arranged from the third port to the fourth port of the four-way switching valve (22). (25) and are arranged.

  The compressor (21) is a scroll type or rotary type hermetic compressor. The four-way switching valve (22) includes a first state (state indicated by a solid line in FIG. 1) in which the first port communicates with the third port and the second port communicates with the fourth port; The port is switched to a second state (state indicated by a broken line in FIG. 1) in which the port communicates with the fourth port and the second port communicates with the third port. The expansion valve (24) is a so-called electronic expansion valve.

  The outdoor heat exchanger (23) exchanges heat between the outdoor air and the refrigerant. The outdoor heat exchanger (23) will be described later. On the other hand, the indoor heat exchanger (25) exchanges heat between the indoor air and the refrigerant. The indoor heat exchanger (25) is constituted by a so-called cross fin type fin-and-tube heat exchanger provided with a heat transfer tube which is a circular tube.

<Operation of air conditioner>
The air conditioner (10) selectively performs a cooling operation, a heating operation, and a defrosting operation.

  In the air conditioner (10) during the cooling operation and the heating operation, the outdoor fan (15) and the indoor fan (16) operate. The outdoor fan (15) supplies outdoor air to the outdoor heat exchanger (23), and the indoor fan (16) supplies indoor air to the indoor heat exchanger (25).

  In the refrigerant circuit (20) during the cooling operation, the refrigeration cycle is performed with the four-way switching valve (22) set to the first state. In this state, the refrigerant circulates in the order of the outdoor heat exchanger (23), the expansion valve (24), and the indoor heat exchanger (25), and the outdoor heat exchanger (23) functions as a condenser. (25) functions as an evaporator. In the outdoor heat exchanger (23), the gas refrigerant flowing from the compressor (21) dissipates heat to the outdoor air and condenses, and the condensed refrigerant flows out toward the expansion valve (24). The indoor unit (12) blows out the air cooled in the indoor heat exchanger (25) into the room.

  In the refrigerant circuit (20) during the heating operation, the refrigeration cycle is performed with the four-way switching valve (22) set to the second state. In this state, the refrigerant circulates in the order of the indoor heat exchanger (25), the expansion valve (24), and the outdoor heat exchanger (23), and the indoor heat exchanger (25) functions as a condenser, and the outdoor heat exchanger (23) functions as an evaporator. The refrigerant that has expanded into a gas-liquid two-phase state when passing through the expansion valve (24) flows into the outdoor heat exchanger (23). The refrigerant flowing into the outdoor heat exchanger (23) absorbs heat from the outdoor air and evaporates, and then flows out toward the compressor (21). The indoor unit (12) blows out the air heated in the indoor heat exchanger (25) into the room.

  During the heating operation in which the outdoor heat exchanger (23) functions as an evaporator, moisture in the outdoor air may become frost and adhere to the surface of the outdoor heat exchanger (23). When frost adheres to the outdoor heat exchanger (23), heat exchange between the refrigerant and the outdoor air is hindered by the frost, and the heating capacity of the air conditioner (10) decreases. Therefore, the air conditioner (10) temporarily stops the heating operation and performs the defrosting operation when the defrosting start condition indicating that a certain amount of frost is attached to the outdoor heat exchanger (23) is satisfied. I do.

  In the air conditioner (10) during the defrosting operation, the outdoor fan (15) and the indoor fan (16) are stopped. In the refrigerant circuit (20) during the defrosting operation, the four-way switching valve (22) is set to the first state, and the compressor (21) is operated. Further, during the defrosting operation, the rotation speed of the compressor (21) is set to the lower limit value. In the refrigerant circuit (20) during the defrosting operation, the refrigerant circulates as in the cooling operation. That is, the high-temperature and high-pressure gas refrigerant discharged from the compressor (21) is supplied to the outdoor heat exchanger (23). The frost adhering to the outdoor heat exchanger (23) is heated and melted by the gas refrigerant. The refrigerant that has passed through the outdoor heat exchanger (23) sequentially passes through the expansion valve (24) and the indoor heat exchanger (25), and is then sucked into the compressor (21) and compressed.

-Outdoor heat exchanger-
The outdoor heat exchanger (23) will be described with reference to FIGS. Note that the number of flat tubes (33) and the number of main heat exchange regions (51a to 51c) and auxiliary heat exchange units (52a to 52c) shown in the following description are merely examples.

<Configuration of outdoor heat exchanger>
As shown in FIGS. 2 and 3, the outdoor heat exchanger (23) includes one first header collecting pipe (first header collecting section) (60) and one second header collecting pipe (second header collecting pipe). Part) (70), a number of flat tubes (33), and a number of fins (36). The first header collecting pipe (60), the second header collecting pipe (70), the flat pipe (33) and the fin (35) are all made of an aluminum alloy and are joined to each other by brazing.

  As will be described in detail later, the outdoor heat exchanger (23) is divided into a main heat exchange section (51) and an auxiliary heat exchange section (52). In this outdoor heat exchanger (23), a part of flat tubes (33b) constitutes an auxiliary heat exchange part (52), and the remaining flat tubes (33a) constitute a main heat exchange part (51). .

  Both the first header collecting pipe (60) and the second header collecting pipe (70) are formed in an elongated cylindrical shape with both ends closed. 2 and 3, the first header collecting pipe (60) is erected at the left end of the outdoor heat exchanger (23), and the second header collecting pipe (70) is erected at the right end of the outdoor heat exchanger (23). It is installed in a state.

  As shown in FIG. 4, the flat tube (33) is a heat transfer tube whose cross-sectional shape is a flat oval. As shown in FIG. 3, in the outdoor heat exchanger (23), the plurality of flat tubes (33) are arranged in a state in which the extending direction is the left-right direction and the flat side surfaces face each other. Further, the plurality of flat tubes (33) are arranged side by side at regular intervals and are substantially parallel to each other. Each flat tube (33) has one end inserted into the first header collecting tube (60) and the other end inserted into the second header collecting tube (70).

  As shown in FIG. 4, each flat tube (33) is formed with a plurality of fluid passages (34). Each fluid passage (34) is a passage extending in the extending direction of the flat tube (33). In each flat tube (33), the plurality of fluid passages (34) are arranged in a line in the width direction of the flat tube (33) (that is, the direction orthogonal to the longitudinal direction). One end of each of the plurality of fluid passages (34) formed in each flat pipe (33) communicates with the internal space of the first header collecting pipe (60), and the other end of each of the plurality of fluid passages (34) is a second header collecting pipe (70). ). The refrigerant supplied to the outdoor heat exchanger (23) exchanges heat with air while flowing through the fluid passage (34) of the flat tube (33).

  As shown in FIG. 4, the fin (36) is a vertically long plate-like fin formed by pressing a metal plate. The fin (36) has a number of elongated notches (45) extending in the width direction of the fin (36) from the front edge of the fin (36) (that is, the edge of the wind main). In the fin (36), a large number of notches (45) are formed at regular intervals in the longitudinal direction (vertical direction) of the fin (36). The portion closer to the lee of the notch (45) forms a tube insertion portion (46). The tube insertion portion (46) has a vertical width substantially equal to the thickness of the flat tube (33) and a length substantially equal to the width of the flat tube (33). The flat tube (33) is inserted into the tube insertion portion (46) of the fin (36) and joined to the peripheral portion of the tube insertion portion (46) by brazing. The fin (36) is formed with a louver (40) for promoting heat transfer. The plurality of fins (36) are arranged in the extending direction of the flat tube (33), thereby partitioning between the adjacent flat tubes (33) into a plurality of ventilation paths (38) through which air flows. .

  As shown in FIG.2 and FIG.3, the outdoor heat exchanger (23) is divided into two heat exchange parts (51,52) up and down. In the outdoor heat exchanger (23), the upper heat exchange part is the main heat exchange part (51), and the lower heat exchange part is the auxiliary heat exchange part (52).

  Each heat exchange section (51, 52) is divided into three heat exchange regions (51a to 51c, 52a to 52c). That is, in the outdoor heat exchanger (23), each of the main heat exchanger (51) and the auxiliary heat exchanger (52) is divided into a plurality of heat exchange regions (51a to 51c, 52a to 52c). ing. In addition, the number of heat exchange regions (51a to 51c, 52a to 52c) formed in each heat exchange section (51, 52) may be two, or may be four or more.

  The main heat exchange section (51) includes, in order from bottom to top, a first main heat exchange region (51a), a second main heat exchange region (51b), and a third main heat exchange region (51c). Is formed.

  The auxiliary heat exchange section (52) includes, in order from the bottom to the top, a first auxiliary heat exchange region (52a), a second auxiliary heat exchange region (52b), and a third auxiliary heat exchange region (52c). Is formed.

  As shown in FIGS. 2 and 3, the internal space of the first header collecting pipe (60) is partitioned vertically by a partition plate (39a). In the first header collecting pipe (60), the main space of the partition plate (39a) is the main header portion (61), and the auxiliary space of the partition plate (39a) is the auxiliary header portion (62).

  The main header part (61) constitutes a communication space corresponding to the main heat exchange part (51). The main header part (61) is a single space communicating with all of the flat tubes (33a) constituting the main heat exchange part (51). That is, the main header portion (61) communicates with the flat tube (33a) of each main heat exchange region (51a to 51c).

  2 and 3, the main header portion (61) of the first header collecting pipe (60) has a first partial space (61a) corresponding to the first main heat exchange area (51a). The second partial space (61b) corresponding to the second main heat exchange region (51b) and the third partial space (61c) corresponding to the third main heat exchange region (51c).

  Further, as shown in FIGS. 2 and 3, a gas side connection pipe (57) is connected to the main header portion (61) of the first header collecting pipe (60). One end of the gas side connection pipe (57) is connected to the substantially vertical center of the main header section (61) in the first header collecting pipe (60), and the second main heat exchange area of the main header section (61). It communicates with the partial space (61b) corresponding to (51b). The other end of the gas side connection pipe (57) is connected to a copper pipe (18) connecting the outdoor heat exchanger (23) and the third port of the four-way switching valve (22) via a joint (not shown). It is connected. The gas side connection pipe (57) is an aluminum alloy member formed in a circular tube shape.

  The auxiliary header part (62) constitutes an auxiliary communication space corresponding to the auxiliary heat exchange part (52). The auxiliary header part (62) is divided into the same number (three in this embodiment) of communication chambers (62a to 62c) as the auxiliary heat exchange regions (52a to 52c). The lowermost first communication chamber (62a) communicates with all the flat tubes (33b) constituting the first auxiliary heat exchange region (52a). The second communication chamber (62b) located above the first communication chamber (62a) communicates with all the flat tubes (33b) constituting the second auxiliary heat exchange region (52b). The uppermost third communication chamber (62c) communicates with all the flat tubes (33b) constituting the third auxiliary heat exchange region (52c).

  The auxiliary header section (62) includes a main horizontal partition plate (80), an auxiliary horizontal partition plate (85), and a vertical partition plate (90). These three partition plates ( The three communication chambers (62a) to (62c) and the mixing chamber (63) are formed by 80), (85), and (90). The mixing chamber (63) is not shown in detail, but the three communication chambers (62a) to (62c) are connected through through holes formed in the three partition plates (80), (85), and (90). ). In addition, one end of the liquid side connecting pipe (55) is opened in the mixing chamber (63), as will be described later.

  The auxiliary header portion (62) of the first header collecting pipe (60) is provided with a liquid side connection pipe (55). One end of the liquid side connecting pipe (55) is connected to the lower part of the first header collecting pipe (60) and communicates with the mixing chamber (63) of the auxiliary header section (62). The other end of the liquid side connection pipe (55) is connected to a copper pipe (17) connecting the outdoor heat exchanger (23) and the expansion valve (24) via a joint (not shown). The liquid side connection pipe (55) is joined to the first header collecting pipe (60) by brazing.

  The internal space of the second header collecting pipe (70) is divided into a main communication space (71) as a main header corresponding to the main heat exchange part (51) and an auxiliary heat exchange part (52) by a partition plate (39b). And an auxiliary communication space (72) as an auxiliary header portion corresponding to the above.

  The main communication space (71) is partitioned up and down by two partition plates (39c). The partition plate (39c) divides the main communication space (71) into the same number (three in this embodiment) of partial spaces (header spaces) (71a to 71c) as the main heat exchange regions (51a to 51c). ing. The lowermost first partial space (71a) communicates with all the flat tubes (33a) constituting the first main heat exchange region (51a). The second partial space (71b) located above the first partial space (71a) communicates with all the flat tubes (33a) constituting the second main heat exchange region (51b). The uppermost third partial space (71c) communicates with all the flat tubes (33a) constituting the third main heat exchange region (51c).

  The auxiliary communication space (72) is vertically partitioned by two partition plates (39d). The partition plate (39d) divides the auxiliary communication space (72) into the same number (three in this embodiment) of partial spaces (header spaces) (72a to 72c) as the auxiliary heat exchange regions (52a to 52c). ing. The lowermost fourth partial space (72a) communicates with all the flat tubes (33b) constituting the first auxiliary heat exchange region (52a). The fifth partial space (72b) located above the fourth partial space (72a) communicates with all the flat tubes (33b) constituting the second auxiliary heat exchange region (52b). The uppermost sixth partial space (72c) communicates with all the flat tubes (33b) constituting the third auxiliary heat exchange region (52c).

  Three connecting pipes (connecting pipes) (76, 77, 78) are attached to the second header collecting pipe (70). One end of the first connection pipe (76) is connected to the lower part of the second partial space (71b) corresponding to the second main heat exchange region (51b), and the other end is connected to the third auxiliary heat exchange region (52c). Are connected to the sixth partial space (72c). The second connection pipe (77) has one end connected to the lower part of the third partial space (71c) corresponding to the third main heat exchange region (51c), and the other end connected to the second auxiliary heat exchange region (52b). Are connected to the fifth partial space (72b). The third connection pipe (78) has one end connected to the lower part of the first partial space (71a) corresponding to the first main heat exchange region (51a) and the other end connected to the first auxiliary heat exchange region ( 52a) is connected to the fourth partial space (72a).

  As can be seen from the enlarged view of the main part of FIG. 5, the first to third connection pipes (76, 77, 78) are all the main header part (71) of the second header collecting pipe (70). The vicinity of the opening end to the lower part of the first to third partial spaces (71a to 71c) has a horizontal portion (76h, 77h, 78h) extending in the horizontal direction, and this horizontal portion (76h, 77h, 78h) is the first. -It is connected to the lower part of the third partial space (71a-71c).

  Further, the horizontal portions (76h, 77h, 78h) of the first to third connection pipes (76, 77, 78) are respectively connected to the main heat exchange portions in the corresponding partial spaces (71a, 71b, 71c). It faces the opening of the end face of the flat tube (33a) located in the lower part of the corresponding main heat exchange area (51a-51c) of (51).

  Thus, in the outdoor heat exchanger (23) of the present embodiment, the first main heat exchange region (51a) and the first auxiliary heat exchange region (52a) are connected in series by the third connection pipe (78). The second main heat exchange area (51b) and the third auxiliary heat exchange area (52c) are connected in series by the first connection pipe (76), and the third main heat exchange area (51c) and the second auxiliary heat exchange area (52c) are connected in series. The heat exchange region (52b) is connected in series with the second connection pipe (77). That is, in the outdoor heat exchanger (23) of the present embodiment, the first auxiliary heat exchange region (52a) corresponds to the first main heat exchange region (51a), and the second auxiliary heat exchange region (52b) is the third. The third auxiliary heat exchange region (52c) corresponds to the second main heat exchange region (51b), corresponding to the heat exchange region (51c).

  From the above configuration, in the present embodiment, during the operation in which the outdoor heat exchanger (23) acts as an evaporator, the lower header portion (62) from the liquid side connection pipe (55) to the first header collecting pipe (60) is provided. ) Flows into the main communication space (71) from the three auxiliary heat exchange regions (52a to 52c) of the auxiliary heat exchange section (52) through the auxiliary communication space (72) of the second header collecting pipe (70). Then, the refrigerant flows through the three main heat exchange regions (51a to 51c) of the main heat exchange section (51) and flows out to the gas side connection pipe (57).

<Refrigerant flow in outdoor heat exchanger / condenser>
During the cooling operation of the air conditioner (10), the outdoor heat exchanger (23) functions as a condenser. The flow of the refrigerant in the outdoor heat exchanger (23) during the cooling operation will be described.

  Gas refrigerant discharged from the compressor (21) is supplied to the outdoor heat exchanger (23). The gas refrigerant sent from the compressor (21) flows into the main header part (61) of the first header collecting pipe (60) through the gas side connection pipe (57), and then the main heat exchange part (51). Are distributed to each flat tube (33a). In each main heat exchange area (51a to 51c) of the main heat exchange section (51), the refrigerant flowing into the fluid passage (34) of the flat tube (33a) dissipates heat to the outdoor air while flowing through the fluid passage (34). Then, it condenses and then flows into the corresponding partial spaces (71a to 71c) of the second header collecting pipe (70).

  The refrigerant that has flowed into the partial spaces (71a to 71c) of the main communication space (71) is sent to the corresponding partial spaces (72a to 72c) of the auxiliary communication space (72). Specifically, the refrigerant that has flowed into the first partial space (71a) of the main communication space (71) passes through the third connection pipe (78) to the fourth partial space (72a) of the auxiliary communication space (72). Flows in. The refrigerant flowing into the second partial space (71b) of the main communication space (71) flows into the sixth partial space (72c) of the auxiliary communication space (72) through the first connection pipe (76). The refrigerant flowing into the third partial space (71c) of the main communication space (71) flows into the fifth partial space (72b) of the auxiliary communication space (72) through the second connection pipe (77).

  The refrigerant flowing into the partial spaces (72a to 72c) of the auxiliary communication space (72) is distributed to the flat tubes (33b) in the corresponding auxiliary heat exchange regions (52a to 52c). The refrigerant flowing through the fluid passage (34) of each flat tube (33b) dissipates heat to the outdoor air and becomes supercooled liquid, and then the corresponding communication chamber of the auxiliary header portion (62) of the first header collecting pipe (60). (62a to 62c). Thereafter, the refrigerant flows into the liquid side connecting pipe (55) through the mixing chamber (63) and flows out of the outdoor heat exchanger (23).

<Flow of refrigerant in outdoor heat exchanger / Evaporator>
During the heating operation of the air conditioner (10), the outdoor heat exchanger (23) functions as an evaporator. The flow of the refrigerant in the outdoor heat exchanger (23) during the heating operation will be described.

  The outdoor heat exchanger (23) is supplied with the refrigerant that has expanded into a gas-liquid two-phase state when passing through the expansion valve (24). The refrigerant that has passed through the expansion valve (24) flows into the mixing chamber (63) in the auxiliary header portion (62) of the first header collecting pipe (60) through the liquid side connecting pipe (55). At that time, in the mixing chamber (63), the flowing refrigerant in the two-phase state collides with the vertical partition plate (90), and the gas refrigerant and the liquid refrigerant in the refrigerant are mixed. The mixed liquid refrigerant is distributed from the mixing chamber (63) to the communication chambers (62a to 62c) in the auxiliary header section (62).

  The refrigerant that has flowed into the communication chambers (62a to 62c) in the auxiliary header portion (62) of the first header collecting pipe (60) flows to the flat tubes (33b) in the corresponding auxiliary heat exchange regions (52a to 52c). Distributed. The refrigerant flowing into the fluid passage (34) of each flat tube (33b) absorbs heat from the outdoor air while flowing through the fluid passage (34), and a part of the liquid refrigerant evaporates. The refrigerant that has passed through the fluid passage (34) of the flat tube (33b) flows into the corresponding partial spaces (72a to 72c) of the auxiliary communication space (72) of the second header collecting pipe (70).

  The refrigerant flowing into the partial spaces (72a to 72c) of the auxiliary communication space (72) is sent to the corresponding partial spaces (71a to 71c) of the main communication space (71). Specifically, the refrigerant that has flowed into the fourth partial space (72a) of the auxiliary communication space (72) passes through the horizontal portion (78h) of the third connection pipe (78) and enters the first communication space (71). It flows horizontally into the lower part of the partial space (71a). The refrigerant flowing into the fifth partial space (72b) of the auxiliary communication space (72) passes through the horizontal portion (77h) of the second connection pipe (77) and passes through the third partial space (71c) of the main communication space (71). ) In the horizontal direction. The refrigerant that has flowed into the sixth partial space (72c) of the auxiliary communication space (72) passes through the horizontal portion (76h) of the first connection pipe (76) and passes through the second partial space (71b) of the main communication space (71). ) In the horizontal direction.

  And the refrigerant | coolant which flowed in the horizontal direction to the lower part of the 1st-3rd partial space (71a-71c) from the horizontal part (76h, 77h, 78h) of the said 1st-3rd connection pipe (76,77,78). Of the first to third main heat exchanging regions (51a to 51c) of the main heat exchanging portion (61) that opens horizontally in the lower side of the first to third subspaces (71a to 71c). The flat tube (33a) flows in the horizontal direction as it is into the flat tube (33a) without changing the flow direction from the end face opening of the flat tube (33a).

  Thereafter, the refrigerant flowing in the horizontal direction through the fluid passage (34) of each flat tube (33a) in the corresponding first to third main heat exchange regions (51a to 51c) of the main heat exchange section (51) It absorbs heat from the outdoor air and evaporates to substantially enter a gas single phase state, and then flows into the main header portion (61) of the first header collecting pipe (60). Thereafter, the refrigerant flows out of the outdoor heat exchanger (23) through the gas side connection pipe (57).

  Here, when the liquid refrigerant is distributed from the mixing chamber (63) to the three communication chambers (62a to 62c) positioned above and below, the communication chamber (62a) positioned at the bottom is caused by the gravity acting on the liquid refrigerant. It is difficult to flow into the communication chamber (62c) located at the uppermost stage. Therefore, the refrigerant that has flowed from the communication chamber (62a) located at the lowermost stage into the lowermost auxiliary heat exchange region (52a) of the auxiliary heat exchange section (52) becomes liquid rich, and the dryness of the inlet is small.

  The liquid-rich refrigerant flows into the fourth partial space (72a) of the auxiliary header portion (72) of the second header collecting pipe (70), and then the horizontal portion (78h) of the third connection pipe (78). ) Through the lower portion of the first partial space (71a) in the lowermost stage of the main header section (71), so that most of the liquid-rich refrigerant flows in the lowermost stage of the main heat exchange section (51). 1 Flow into the flat tubes (33a) that open to the lower side of the main heat exchanger (51a), and reduce the dryness of the outlet of the refrigerant in these flat tubes (33a). Refrigerating machine oil is prevented from accumulating. As a result, the amount of refrigerating machine oil accumulated in the first to third main heat exchange regions (51a) to (51c) of the main heat exchange section (51) becomes substantially equal.

  In addition, the end face opening of the horizontal portion (78h) of the third connection pipe (78) is a flat tube disposed horizontally below the first main heat exchange region (51a) of the main heat exchange portion (51). Since it faces the end surface opening of (33), the refrigerant flowing in the horizontal direction from the third connection pipe (78) into the lower portion of the first partial space (71a) flows into the first main heat exchange region (51a). The flow rate of the liquid refrigerant flowing into the flat tubes (33) located in the lower part of the flat tubes (33) as they flow in the horizontal direction is ensured. Therefore, the superheated state of the refrigerant flowing through these flat tubes (33) is further suppressed, and the amount of refrigerating machine oil accumulated in these flat tubes can be further reduced.

<Flow of refrigerant in outdoor heat exchanger / During defrosting operation>
When a predetermined defrosting start condition is satisfied during the heating operation, the air conditioner (10) temporarily stops the heating operation and performs the defrosting operation. During the defrosting operation of the air conditioner (10), the outdoor heat exchanger (23) performs a defrosting operation.

  When the defrosting operation of the air conditioner (10) is started, the high-temperature and high-pressure gas refrigerant discharged from the compressor (21) passes through the gas side connection pipe (57) and the first header collecting pipe (60). Into the main header section (61). The gas refrigerant that has flowed from the main header portion (61) into the flat tube (33a) of the main heat exchange region (51a to 51c) dissipates heat and condenses. The frost adhering to the outdoor heat exchanger (23) is heated and melted by the gas refrigerant.

  At this time, as described above, since the amount of refrigerating machine oil accumulated in the first to third main heat exchange regions (51a) to (51c) of the main heat exchange section (51) is substantially equal, these main heat exchanges The refrigerating machine oil accumulated in the flat tubes (33a) in the regions (51a) to (51c) has the same degree of refrigerant flow resistance, and the main heat exchange regions (51a) to (51c) are mutually connected. An almost equal amount of gas refrigerant flows. As a result, the defrosting of these main heat exchange areas (51a) to (51c) proceeds at the same level, and the defrosting is completed almost simultaneously in all the main heat exchange areas (51a) to (51c). Driving will be completed early.

<Effect of this embodiment>
Therefore, in the present embodiment, in the second header collecting pipe (70), the first partial space (71a) at the lowest level of the main communication space (71) and the fourth partial space at the lowest level of the auxiliary communication space (72) ( 72a) is connected to the third connecting pipe (78), and this third connecting pipe (78) is horizontally connected to the lower part of the first partial space (71a) at the lowest stage of the main communication space (71). The liquid-rich refrigerant that has flowed into the first auxiliary heat exchange region (52a) at the lowermost stage of the auxiliary heat exchanger (52) is used as the first main heat at the lowermost stage of the main heat exchanger (51). It is possible to flow a large amount into the flat tube (33a) located at the lower part of the exchange region (51a). Therefore, the overheating state of the refrigerant flowing in these flat tubes (33a) can be suppressed, and the amount of refrigeration oil accumulated in these flat tubes (33a) can be limited to a small amount. Can be terminated.

  Moreover, the end surface opening of the horizontal portion (78h) of the third connection pipe (78) is opposed to the end surface opening of the flat tube (33a) located under the first main heat exchange region (51a). Therefore, it is possible to secure a large flow rate of the liquid refrigerant flowing through these flat tubes (33), and to further reduce the amount of refrigerating machine oil accumulated in these flat tubes.

<Second Embodiment>
Next, a second embodiment of the present invention will be described with reference to FIG.

  In the first embodiment, the auxiliary header portion is connected to the lowermost first partial space (71a) of the main header portion (71) of the second header collecting pipe (70) via the third connection pipe (78). The second partial space (71b) of the main header portion (71) is connected to the lowermost fourth partial space (72a) of (72) through the first connection pipe (76) and the auxiliary header portion (72 In this embodiment, the lowermost first partial space (71a) of the main header portion (71) is assisted through the third connection pipe (78). The auxiliary header portion is connected to the sixth partial space (72c) at the uppermost stage of the header portion (72), and the second partial space (71b) of the main header portion (71) is connected via the first connection pipe (76). It is connected to the lowermost fourth partial space (72a) of (72). Other configurations are the same as those in the first embodiment.

  In the present embodiment, as described above, when the liquid refrigerant is distributed from the mixing chamber (63) to the three communication chambers (62a to 62c) positioned above and below, the liquid refrigerant is moved to the lowermost stage by the gravity acting on the liquid refrigerant. It is easy to flow into the communication chamber (62a) located and difficult to flow into the communication chamber (62c) located at the uppermost stage. Accordingly, the refrigerant that has flowed from the communication chamber (62c) located at the uppermost stage into the uppermost auxiliary heat exchange region (52c) of the auxiliary heat exchanging section (52) becomes gas-rich, and the degree of dryness of the inlet is large. However, this refrigerant flows into the sixth partial space (72c) of the auxiliary header part (72) of the second header collecting pipe (70) and then passes through the horizontal part (78h) of the third connection pipe (78). Since the liquid flows in the horizontal direction into the lower part of the first partial space (71a) of the main header part (71), the liquid refrigerant contained in the gas-rich refrigerant is the first main heat exchange part (51a) of the main heat exchange part (51). A large amount of fluid flows into the flat tubes (33a) that open to the lower side of the refrigerant, and the refrigerant dryness of these flat tubes (33a) decreases, and refrigeration oil accumulates in these flat tubes (33a). It is suppressed. As a result, the amount of refrigerating machine oil accumulated in the first to third main heat exchange regions (51a) to (51c) of the main heat exchange section (51) becomes substantially equal, and the defrosting operation performed thereafter is performed. It can be completed early.

<Third Embodiment>
Next, a third embodiment of the present invention will be described with reference to FIGS.

  In the said 1st Embodiment, in the outdoor heat exchanger (23), the main heat exchange part (51) which has three main heat exchange area | regions (51a-51c), and three auxiliary heat exchange area | regions (52a-52c) However, in this embodiment, the main heat exchanging part (51) and the auxiliary heat exchanging part (52) are each divided into three heat exchanging regions (51a to 51c). , (52a to 52c) is the same as that of the first embodiment, but auxiliary heat exchange is provided below each of the three main heat exchange regions (51a to 51c) of the main heat exchange section (51). The structure which arrange | positioned the corresponding auxiliary heat exchange area | region (52a-52c) of a part (52), specifically, auxiliary heat exchange below the 1st main heat exchange area | region (51a) of a main heat exchange part (51). The first auxiliary heat exchange region (52a) of the section (52) is disposed, and the auxiliary heat is located below the second main heat exchange region (51b) located above the first main heat exchange region (51a). A second auxiliary heat exchange area (52b) of the exchange section (52) is disposed, and the second main heat exchange area (52b) is arranged. The present invention is configured such that the third auxiliary heat exchange region (52c) of the auxiliary heat exchange section (52) is disposed below the third main heat exchange region (51c) located above the exchange region (52b). It is applied.

  That is, in this embodiment, as shown in FIGS. 7 and 8, the second header collecting pipe (70) corresponds to the three main heat exchange regions (51a to 51c) of the main heat exchange section (51). The header space corresponding to the three heat exchange regions (52a to 52c) of the auxiliary heat exchange section (52) is partitioned by five partition plates (39e), and the first to sixth portions Spaces (71a to 71c) and (72a to 72c) are formed, and the first partial space (71a) corresponding to the first main heat exchange region (51a) of the main heat exchange section (51) and the auxiliary The fourth partial space (72a) corresponding to the first auxiliary heat exchange region (52a) of the heat exchange part (52) is connected by the third connection pipe (78), and the main heat exchange part (51) The second partial space (71b) corresponding to the second main heat exchange area (51b) and the fifth partial space (52b) corresponding to the second auxiliary heat exchange area (52b) of the auxiliary heat exchange section (52) 72b) is connected to the second connection pipe (76), and the third main heat exchange section of the main heat exchange section (51) The third partial space (71c) corresponding to (51c) and the sixth partial space (72c) corresponding to the third auxiliary heat exchange region (52c) of the auxiliary heat exchanging portion (52) are in the second connection. Connected with pipe (77).

  Similarly to the first embodiment, the first to third connecting pipes (76) to (78) are respectively the first header section (71) of the main header section (71) of the second header collecting pipe (70). ~ The open end to the lower part of the third partial space (71a-71c) has a horizontal part (76h, 77h, 78h) extending in the horizontal direction, and these horizontal parts (76h, 77h, 78h) correspond Are connected to the lower part of the partial spaces (71a to 71c) to be connected from the horizontal direction.

  Furthermore, the end surface openings of the horizontal portions (76h, 77h, 78h) of the first to third connection pipes (76, 77, 78) are respectively in the corresponding partial spaces (71a, 71b, 71c). , Facing the end face opening of the flat tube (33a) located in the lower part of the corresponding main heat exchange area (51a to 51c) of the main heat exchange part (51).

  Therefore, in the present embodiment, as in the first embodiment, liquid is applied to the flat tube (33a) that opens at the lower side of the first main heat exchange part (51a) of the main heat exchange part (51). Since it is possible to limit the amount of refrigerating machine oil that flows in a large amount of refrigerant and accumulates in these flat tubes (33a), the defrosting operation performed thereafter can be completed at an early stage, and the first to third connections Since the length of the piping (76, 77, 78) can be made equal, the set of the first main heat exchange area (51a) and the first auxiliary heat exchange area (52a) and the second main heat Between the pair of the exchange area (51b) and the second auxiliary heat exchange area (52b) and the pair of the third main heat exchange area (51c) and the third auxiliary heat exchange area (52c) The passage length of the refrigerant can be made substantially equal.

(Other embodiments)
The present invention may be configured as follows for the first to third embodiments.

  In the above embodiment, the main heat exchanging section (51) is divided into three main heat exchanging areas (51a) to (51c), and the auxiliary heat exchanging section (52) is also divided into three auxiliary heat exchanging areas (52a) to (52c). However, the present invention is not limited to this, and may be divided into two or four or more. Even in this case, each main heat exchange area of the main heat exchange section is connected to a corresponding auxiliary heat exchange area of the auxiliary heat exchange section via a connection pipe.

  Further, in the above-described embodiment, for example, during operation that functions as an evaporator, the auxiliary heat exchange unit (52) is passed from the liquid side connection pipe (55) through the lower header part (62) of the first header collecting pipe (60). The refrigerant flowing into the three auxiliary heat exchange regions (52a to 52c) flows to the right in FIG. 2 and into the second header collecting pipe (70), and then flows through the second header collecting pipe (70). Is folded in the left direction and is passed through the three main heat exchange regions (51a to 51c) of the main heat exchange section (51), and then flows out to the gas side connection pipe (57). The present invention is not limited to this configuration, and a configuration in which the refrigerant flow direction is folded twice, for example, may be employed. For example, two main heat exchange sections and two auxiliary heat exchange sections are provided, and the refrigerant flowing from the first auxiliary heat exchange section into the second header collecting pipe (70) during the operation of functioning as an evaporator is supplied to the second header collecting pipe (70). Folded at the header collecting pipe (70) and flowed into the first header collecting pipe (60) through the first main heat exchange section, and then turned back at the first header collecting pipe (60) and second auxiliary heat exchange. It is also possible to adopt a configuration in which the air is poured into the second header collecting pipe (60) through the section, folded back at the second header collecting pipe (60), and poured into the second main heat exchange section.

  Furthermore, in the above embodiment, the liquid side connecting pipe (55) and the gas side connecting pipe (57) are connected to the first header collecting pipe (60), but in addition, the liquid side connecting pipe (55) and A configuration may be adopted in which any one of the gas side connection pipes (57) is connected to the first header collecting pipe (60) and the other is connected to the second header collecting pipe (70).

  As described above, the present invention is useful when applied to a heat exchanger that includes a flat tube and a header collecting tube and exchanges heat between the refrigerant and air.

20 refrigerant circuit 23 outdoor heat exchanger 33 flat tube 33a flat tube 33b constituting the main heat exchange portion flat tube 36 constituting the auxiliary heat exchange portion Fin 51 main heat exchange portion 51a first main heat exchange region 51b second main heat Exchange area 51c Third main heat exchange area 52 Auxiliary heat exchange part 52a First auxiliary heat exchange area 52b Second auxiliary heat exchange area 52c Third auxiliary heat exchange area 60 First header collecting pipe 70 Second header collecting pipe 71 Main communication Space (main header part)
71a First partial space (first header space)
71b Second partial space (second header space)
71c Third partial space (third header space)
72 Auxiliary communication space (auxiliary header)
72a Fourth partial space (fourth header space)
72b 5th partial space (5th header space)
72c Sixth partial space (sixth header space)
76 First connection piping (communication piping)
77 Second connection piping (communication piping)
78 Third connection piping (communication piping)

Claims (4)

A main heat exchange section (51) and an auxiliary heat exchange section (52) in which a plurality of flat tubes (33) each having a refrigerant passage formed therein are vertically divided, and both the heat exchange sections (51), (52) A header assembly part (70) having a main header part (71) and an auxiliary header part (72) to which the ends of the main heat exchange part (71) are connected, Each is divided into a plurality of heat exchange regions (51a-51c), (52a-52c) in the upper and lower sides,
When operating as an evaporator, the refrigerant passes through the auxiliary header section (72) of the header assembly section (70) from the plurality of heat exchange regions (52a to 52c) of the auxiliary heat exchange section (52), and the header assembly section (70). A heat exchanger having a refrigerant flow path that circulates from the main header portion (71) to the plurality of heat exchange regions (51a to 51c) of the main heat exchange portion (51),
The header space (72a to 72c) and the main header portion (71) corresponding to the plurality of heat exchange regions (52a to 52c) of the auxiliary heat exchange portion (52) of the auxiliary header portion (72) of the header assembly portion (70). ) Of the main heat exchanging part (51) of the plurality of heat exchanging regions (51a-51c) corresponding to the header space (71a-71c) respectively connecting pipes (76-78),
The plurality of connecting pipes (76 to 78) are respectively corresponding to the main heat exchange section (51) in the corresponding header space (72a to 72c) of the main header section (71) of the header assembly section (70). A heat exchanger having a horizontal opening at a lower portion of the heat exchange area (51a to 51c). The heat exchanger according to claim 1,
The end face openings of the plurality of connecting pipes (76 to 78) are respectively the end face openings of the flat tubes (33a) located below the corresponding heat exchange regions (51a to 51c) of the main heat exchange section (51). Heat exchanger characterized by facing the part. In the heat exchanger according to claim 1 or 2,
The header space (72a) corresponding to the lowermost heat exchange area (52a) of the auxiliary heat exchange part (52) of the auxiliary header part (72) of the header assembly part (70), and the main header part (71) A heat exchanger, characterized in that a header space (71a) corresponding to the lowermost heat exchange region (51a) of the main heat exchange part (51) is connected by a connecting pipe (78). In the heat exchanger according to claim 1 or 2,
The header space (72c) corresponding to the uppermost heat exchange area (52c) of the auxiliary heat exchange section (52) of the auxiliary header section (72) of the header assembly section (70), and the main header section (71) A heat exchanger, characterized in that a header space (71a) corresponding to the lowermost heat exchange region (51a) of the main heat exchange part (51) is connected by a connecting pipe (78).

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